Throttle-relay.



Nol 873,729.

PTENTED DEG, ."L'g QG?. A. S, OUBITT. 'lHROTTLB RELAY: APPLICATION NLED MAE.31.1906.

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UNITED STATES PATENT OFFIOE.

ARCHIBALD S. OUBITT, OF SCHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY; A CORPORATION OF NEW YORK.

THROTTLE-RELAY.

Specification of Letters Patent.

Patented Dec. 1'7. i am' Application ned Mimi 31. 190e. serai No. 309.124.

relays and more particularly relays adapted to govern circuit-controlling devices in order to prevent the circuit conditions from becom ing abnormal. In motor control systems for example, controlling devices of some sort are. used for decreasing resistance of the motor circuit or otherwise gradually changing the circuit conditions in accelerating the motor so as to bring it from rest up to speed. It is common to provide .means controlled by the motor current for preventing `thecontrolling device from being carelessly operated so as to subject the motor to too great a rush of current. A satisfactory arrangement consists in a locking device for the controller which locking device is in turn governed by a relay having its windings in the motor circuit; and, in order to make .this relay as small as possible and still secure considerable torque, thc movable member of the relay usually comprises an iron plunger. The presence of the iron core or plunger, however, makes the relay less sensitive, since a much larger current is required to lift the plunger than to maintain it lifted. Therefore, if the parts are so proportioned that the relay oper- 'ates to c-ause the controller to be locked when the motor current reaches a predetermined value, unlocking of the controller does not' take place until the current has fallen materially below that value, namely, below a l value which is entirely safe.

The object of the present invention is to make a relay of the character described more sensitive so that it will open and close within parrower limits of current value than heretoore.

To the above end the present' invention contemplates the Vuse of an auxiliary winding on the relay so arranged as to compensate for the difference in pull required to lift the plunger and to maintain it in its lifted position. This coil may either be arranged sol as to normally assist the main coiland to be cut out when the relay has operated, or the auxiliary coil may be one Whichiis...normally idle but which, after the relay-has been operated, becomes energized-and opposes. the action of the main Winding. In this way the effective pull upon the plunger immediately decreases u on the operation of the relay, so that the p unger of the relay may drop upon a much smaller decrease in the motor current than would be the case without the auxiliary winding.

The present invention will be more clearly understood from the following detailed description taken inconnection with the accompanying drawing wherein Figure 1 shows diagrammatically a motor controlled system having a throf tle relay arranged in accordance with the present invention; Fig. 2 is a front elevation of the throttlerelay; Fig. 3 is a longitudinal.cross-section of the relay; and Fig. 4 shows diagrammatically a further modiication of relay.

Referring to Fig. 1: M is a motor, itl, R2 and R are resistance sections adapted to be introduced into the motor circuit and eliminated therefrom in accelerating; O is a motor controller of the separately actuatedA contact type adapted to connect the motor toa source of current supply aniL to control with the exception of the relay, may be or" any usual or preferred types, more than one motor may be used, and the method of changing the circuit conditions to vary the speed of the motor may be any of the methods commonly employed for this purpose.

The relay A consists of a plunger l carrying contact members 2 and 3 adapted to bridge fixed contacts 4 and 5. This plunger is adapted to move within a coil 6 arranged in the motor circuit and a second coil 7 which may conveniently be situated in the control circuit. The contacts 2 and 4, when the relay is in its normal position, break the circuit of the coil 8 of the locking device; while the contacts 3 and 5, when the relay is in the same position, opens a shunt about the coil 7. The coils 6 and 7 are wound so as to assist eachother in lifting the plunger. Thus, when the circuit conditions are such that the plunger of the relay is lifted, the closing ol the contacts 2 and 4 completes the circuit of the lock coil 8 and the contacts 3 and 5` complete the short-circuit about the coil 7. As soon as the coil 7 is short-circuited the infiuence of this coil is eliminated and the plunger is maintained raised solely through the action of the coil 6. It is evident that the coils 6 and 7 may be so proportioned that the plunger will drop again after the current in the motor 'circuit has decreased to any desired value below the value which is required for the operation of the relay.

The operation of the articular .system illustrated is as/follows: Wp

. rent flows from one Vterminal 9 of the source tor circuit is now from terminal 9, through switches T, T1, T2, through resistances R1, R2

and R3, through the coil 6 of the relay, through the motor, to ground. In the second position of the master controller contact 14 engages with contact 15.and switch r1, governing resistance section R1 1s closed.

Thus resistance section R1 is short-circuited and the current to the motor increased.4 If the short-circuiting of the resistance section causes the motor current to rise above a predetermined value, the combined action of the coils 6 and 7 lifts the plunger of the relay and causes the master controller to be locked against further forward movement until the motor current has again fallen to a second predetermined value. In the same way, in the third and fourth positions of -the controller, the switches r2 and 1" are closed and resistance sections R2 and R3 are short-circuited, and the relay and controller lockin device operate in the manner described to ock the controller against further movement when in either of these positions of the controller the motor current rises.beyond the value desired.

In Figs. 2 and 3 .I have illustrated the actual construction of the relay A. The coils 6 and 7 are preferably supported Within a U- shaped frame 16 which, together with a plug 17 and the plunger 1, make a complete magnetic circuit for the coils when the plunger is raised. The contact members 2 and 3 preferably take the form of disks -loosely arranged upon the plunger the disk 2 being supported upon a spring 18 which in turn rests upon a collar 19 fixed to the lunger. The disk 3 rests upon a collar 20 on t e plunger and between the upper side of the disk and a collar 21 is arranged a spring 22. .This latter disk, together with the fixed contact pieces 5, is made of magnetic material; the pieces 5 being normally magnetized by means of coils 23 surrounding them. Thus hen the controller is turned to the first running position, cur-f' when the plunger rises, the disks engage with their res ective fixed contacts; but when the plunger egins tc drop, the disk 3 is magnetically held in its raised osition'in contact with the members' 5 unt' the plunger has left the field of Winding 7. Thereupon the plunger strikes the disk a slight blow and the spring 22 which has been com ressed during the downward movement o the plunger, quickly throws the disk downward to break contact.v It will be' seen that by this ar-A rangement the short-circuit about the coil 7 is not broken until the plunger has reached a point at which the effect of the coil 7 is insufficient to cause the plunger to be a ain lifted before the current through the Win ing 6 has risen to the desired point.

In Fig. 4 I have vshown a modification wherein the contacts 3 and 5 normally short-circuit the coil 7, this coil being wound so as to oppose the coil 6. In this modification the plunger 1a is lifted-entirely through the actionof the main coil 6 and the influence of this coil is weakened when the coil 7 is cut ,in In this modification the spring`22- is arranged beneath the disk 38L so that the contacts 3a and 5 are not separated until thel plunger has substantially reached its elevated position.

It will be noted thatjthe circuit including coils 7 and 7a carries currents which vary as ther master controller is operated and the effect of these coils may thus be automatically TheA particular ioo throttle relay in an automatic controller such f as shown in Patent 763,658, granted on June 28, 1904, on an application. filed by E. R.

Carichoff. Moreover the present invention,

iio

is applicable to other circuits than motor ciry cuits.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. In a system of control, a motor, a controller for varying the motor circuit, a locking device for said controller including a throttle relay havin one coil in series with'. the motor and anot er coil in shunt to the motor, to ether with contacts on said relay for contro ling the circuit of the coil in shunt to the motor. i

2. In a system of control, a motor,I a controller for varying the motor circuit, a locking device for the controller including a throttle relay having a coil in seriesvn'th the motor and an auxiliary coil in shunt to the motor, and contacts on the relay for controliis lin the circuit of said auxiliary coil, said coi s being so proportioned that the cumulae tive efforts thereof serve to operate the relay upon a predetermined current in the motor circuit. i j v 3. In a 'system of control, a motor, a controller for varying the motor circuit, 'a locking device for the controller including a throttle'relay having a coil in the motor cir cuit and an auxiliary coil in shunt to the motor, and contacts on said relay for opening and closing the circuit containing said yaux,n

iliary coil, said coils being proportioned4 and arranged to operate the relay upon a predetermined value of the motor current andthe effective pull upon the movable member of the relay to be diminishedupon the operation of the relay.

4. In a system of control, a motor, a controller for varyin the motor circuit, a locking device -for t e controller including a throttle relay having a coil in the motor circuit andv an auxiliary coil in shunt to the motor, and contacts associated with the relay for denergizing the auxiliary coilyin one of the positions of the relay, said coils being so proportioned and arranged that the relay operates to cause the controller to belocked when the motor current reaches a predetermined value and the effective pull upon the movable member of the relay to be decreased upon the operation of the relay.

5. In a system of control, an electric circuit, means for varying the conditions of said circuit,- a device for retarding the operation of said means including aY rthrottle relay adapted to operate when the current in said circuit reaches a predetermined value, and

` means for weakening the effective holding force ofthe relay after the relay has operated.

6. In a system of control, anelectric circuit, means for varying the conditions of said circuit, a device for retarding the operation of said means including a relay having a plunger which is adapted to be operated when the current in said circuit reaches a predetermined maximum, and means for decreasing the pull upon the plunger upon the operation Iof the relay.

7.vv In al system of control, an electric cir cuit, means for varying the conditions ci said circuit a device Jfor retarding the operation of said y A movable Vplunger and rcoil connected in said circuit,an auxiliary coil on said relay, and means associated with said plunger for respectively energizing and denergizing said auxiliary coil in the two positions ci the plunger, the parts being arranged to cause the plunger to be lifted when the current in said circuit reaches a predetermined value and the pull upon the plun er to be weakened upon the operation of t e plunger.

means including a relay having a 8: In a system of control, a motor circuit, i

a controller for varying the resistance of the motorcircuit, means for retarding the operation of the controller includin a throttle relay having a plunger .adapte to operate when thecurrent in the motor circuit reaches a predetermined maximum, and means for wea-kening the effective pull upon the plunger after the relay has operated.

9. In a system of control, a motor circuit,

a controller for varying the resistance of the motor circuit, means for controlling thel op# eration of said controller including a throttle relay having av movable -plunger and main and auxiliary coils, said main coil being in the motor circuit and said auxiliary coil being energized and, denergized respectively in the two positions ofthe relay, the iarrangement being suclithat the relay plunger is operated when the current in the motor circuit reaches a predetermined maximum and the effective pull upon the plu, ger is diminished upon the operation thereof.

In witness whereof, I have hereunto set my hand this 30th day of March, 1906.

ARCHIE S. CUBITT. Witnesses: BENJAMIN B. HULL, HELEN OEFoRn. 

